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Xiaoyue Ni, a materials science graduate student working with Professor Julia Greer, has shown that metals undergo permanent deformation even prior to yielding—the threshold at which a material under strain becomes permanently deformed. "What Xiaoyue's data are showing is that from the first moment you start deforming it, the dislocations start being active," Greer says. Now that we know how to do this, we can probe a variety of different classes of materials. [Caltech story]

Professor Tapio Schneider has helped bring artist Karen LaMonte's cloudy vision to life. "I thought it was a great idea," says Schneider, whose work focuses on reducing uncertainties in climate change projections—in part through modeling cloud formation to better understand clouds' impact on the environment. Collaborating with LaMonte, he reasoned, could help raise awareness of these issues. "Clouds are hugely important for the climate," says Schneider. "How much warmer it will get depends on what happens to cumulus clouds like those Karen was interested in. " [SoCaltech story]

Professor Ali Hajimiri and colleagues have developed a new camera design that replaces the lenses with an ultra-thin optical phased array (OPA). The OPA does computationally what lenses do using large pieces of glass: it manipulates incoming light to capture an image. "Here, like most other things in life, timing is everything. With our new system, you can selectively look in a desired direction and at a very small part of the picture in front of you at any given time, by controlling the timing with femto-second—quadrillionth of a second—precision," says Professor Hajimiri. [Caltech story] [ENGenious silicon photonics feature]

Professor Andrei Faraon, graduate student Ehsan Arbabi, and their colleagues have developed a metasurface or a sheet of material that can be altered on demand to exhibit properties not usually found in natural materials. For example, materials engineered at the nanoscale can control the dispersion of light and could be the basis of next-generation spectrometers and other imaging devices. [Caltech story]

Senior Daniel Lim has received the 2017 Library Friends' Senior Thesis Prize for his work on sculpting nanofilms with laser illumination. Lim's thesis, titled "Revolution in large-area curved surface lithography: Nanofilm sculpting by thermocapillary modulation," is based on experimental research he conducted over two years in the laboratory of Professor of Applied Physics, Aeronautics, and Mechanical Engineering Sandra M. Troian. "Our group has been working on thermocapillary sculpting of nanofilms for several years now,” says Troian. "Daniel advanced this concept by demonstrating an inverse projection method, which imbues the sculpting process with far greater versatility. Daniel is an exceptional student—a rare combination of superb talent, tremendous drive, utmost professionalism, and entrepreneurial chops. " [Caltech story]

For the first time, Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, and colleagues have been able to directly observe the ultrafast motion of electrons immediately after they are excited with a laser—and found that these electrons diffuse into their surroundings much faster and farther than previously expected. "Our work shows the existence of a fast transient that lasts for a few hundred picoseconds, during which electrons move much faster than their room-temperature speed, implying that they can cover longer distances in a given time when manipulated with lasers," says Professor Bernardi. "This non-equilibrium behavior could be employed in novel electronic, optoelectronic, and renewable energy devices, as well as to uncover new fundamental physics." [Caltech story]

Engineers at the Optical Imaging Laboratory led by Professor Lihong Wang have developed an imaging technology that could help surgeons removing breast cancer lumps confirm that they have cut out the entire tumor—reducing the need for additional surgeries. “What if we could get rid of the waiting? With 3D photoacoustic microscopy, we could analyze the tumor right in the operating room, and know immediately whether more tissue needs to be removed,” Professor Wang explains. [Caltech story]

Lihong Wang, Bren Professor of Medical Engineering and Electrical Engineering, and colleagues are now able to take a live look at the inner workings of a small animal with enough resolution to see active organs, flowing blood, circulating melanoma cells, and firing neural networks. "Photoacoustic tomography combines light and sound synergistically for high-resolution imaging of molecular contrast," says Professor Wang. [Caltech story] [Read the paper]

Aaron Ames, Bren Professor of Mechanical and Civil Engineering, handbuilds bipedal robots and designs the algorithms that govern how they walk. These algorithms couple efficiency equations with boundary constraints to teach robots to generate their own walking gait. [Interview with Professor Ames]